Hi Olga,
On the existing staging environment (the one you made some modification to, with all plugins deactivated, where you already MADE the BRANDS pages work somehow PRIOR to the upgrade/fix), all shop pages on the upgraded theme are NOT working https://staging-funfashion.kinsta.cloud/shop/
I can also rebuild the staging site AS IS without YOUR modification, to see the BRANDS pages would work at all. Let me know.
In any case, the issue is NOT resolved. As I mentioned previously it is NOT only on BRANDS pages but also ALL shop pages (with EXCEPTION of PRODUCT CATEGORIES pages, which are working fine).
Please investigate, let me know if you need me to rebuild the staging site to specific version.
Thank you!